Office 365 - How to view signed message (S/MIME) in Outlook Web App?

When reading signed message from Outlook Web App, the reading pane (preview pane) shows the following:

• S/MIME isn't supported in Conversation view. To view this message in a new window, click here.

In order to view the message content, you may just open the message by clicking the link or double click on the message. Another way is to turn off the Conversations view:

1. click CONVERSATIONS BY DATE (just under the search box)
2. under CONVERSATIONS, select off

You may also using the option "open in separate window", which is located in the  menu options of the OWA interface. For iPad users, please click on the eye glass button on the lower right corner (required to select "Sort by date" under the options).

Some user reported that there is problem viewing signed message (S/MIME) using the Safari browser. If you have such a problem, please use other web browsers like IE, Chrome, etc.

How to verify the digital signature?

If you would like to verify the digital signature, you must use Internet Explorer to view the message by installing the required S/MIME control when prompted:

After you have installed the S/MIME control with Internet Explorer, you can verify if digital signature on the message is trusted or not.